Since I'm constantly seeing people whining about these kinds of questions....

Bookmark this: http://home.paulschou.net/tools/xlate/
Alternative: (Also does ROT13) http://www.asciitohex.com/ (Thanks Desidiosus)

Now go there, copy and paste this sentence into the box labelled "Text" and click the "Encode" button underneath it.

That sentence is your plaintext. Look at the other boxes. You should see the following:

Binary:
01001110 01101111 01110111 00100000 01100111 01101111 00100000 01110100 01101000 01100101 01110010 01100101 00101100 00100000 01100011 01101111 01110000 01111001 00100000 01100001 01101110 01100100 00100000 01110000 01100001 01110011 01110100 01100101 00100000 01110100 01101000 01101001 01110011 00100000 01110011 01100101 01101110 01110100 01100101 01101110 01100011 01100101 00100000 01101001 01101110 01110100 01101111 00100000 01110100 01101000 01100101 00100000 01100010 01101111 01111000 00100000 01101100 01100001 01100010 01100101 01101100 01101100 01100101 01100100 00100000 00100010 01010100 01100101 01111000 01110100 00100010 00100000 01100001 01101110 01100100 00100000 01100011 01101100 01101001 01100011 01101011 00100000 01110100 01101000 01100101 00100000 00100010 01000101 01101110 01100011 01101111 01100100 01100101 00100010 00100000 01100010 01110101 01110100 01110100 01101111 01101110 00100000 01110101 01101110 01100100 01100101 01110010 01101110 01100101 01100001 01110100 01101000 00100000 01101001 01110100 00101110

Hex:
4e 6f 77 20 67 6f 20 74 68 65 72 65 2c 20 63 6f 70 79 20 61 6e 64 20 70 61 73 74 65 20 74 68 69 73 20 73 65 6e 74 65 6e 63 65 20 69 6e 74 6f 20 74 68 65 20 62 6f 78 20 6c 61 62 65 6c 6c 65 64 20 22 54 65 78 74 22 20 61 6e 64 20 63 6c 69 63 6b 20 74 68 65 20 22 45 6e 63 6f 64 65 22 20 62 75 74 74 6f 6e 20 75 6e 64 65 72 6e 65 61 74 68 20 69 74 2e

Base64:
Tm93IGdvIHRoZXJlLCBjb3B5IGFuZCBwYXN0ZSB0aGlzIHNlbnRlbmNlIGludG8gdGhlIGJveCBsYWJlbGxlZCAiVGV4dCIgYW5kIGNsaWNrIHRoZSAiRW5jb2RlIiBidXR0b24gdW5kZXJuZWF0aCBpdC4=

ASCII Dec/Char:
78 111 119 32 103 111 32 116 104 101 114 101 44 32 99 111 112 121 32 97 110 100 32 112 97 115 116 101 32 116 104 105 115 32 115 101 110 116 101 110 99 101 32 105 110 116 111 32 116 104 101 32 98 111 120 32 108 97 98 101 108 108 101 100 32 34 84 101 120 116 34 32 97 110 100 32 99 108 105 99 107 32 116 104 101 32 34 69 110 99 111 100 101 34 32 98 117 116 116 111 110 32 117 110 100 101 114 110 101 97 116 104 32 105 116 46

Now, whenever you see a big bunch of characters, you should be able to recognise how they were encoded. To get from the encoded text to an unknown plaintext, simply copy and paste the "big bunch of characters" into the appropriate box and click the "Decode" button underneath it.

E.g. If you saw this, you'd copy and paste it into the Binary box and click "Decode"
01010100 01101000 01101001 01110011 00100000 01101001 01110011 00100000 01100001 01101110 00100000 01100001 01101110 01110011 01110111 01100101 01110010 00101110

Text:
This is an answer.

"But wait! I copied and pasted into the right box, but there's more numbers in the text box??!!11!!ONE"
Well, what does the text look like? Does it look like any of the kinds of encoding above? Guess what you have to do? That's right, copy and paste that text into the appropriate box and click "Decode". Repeat this until you get to some real text!

The text you get could be:

• A 5 character code that you add to: http://www.steamgifts.com/giveaway/ to get a valid giveaway URL;
• The whole giveaway URL; or
• A question, clue or link to another part of the puzzle.

Practice Questions

Try and solve the following practice questions (they all lead to public giveaways):
1)
aHR0cDovL3d3dy5zdGVhbWdpZnRzLmNvbS9naXZlYXdheS9FWHZ2My9zaWQtbWVpZXJzLWNpdmlsaXphdGlvbi12LWdhbWUtb2YtdGhlLXllYXI=

2)
73 5a 67 7a 61

3)
MDEwMDExMTAgMDExMDEwMTAgMDExMDAxMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMDAwMDEgMDExMDAxMTEgMDEwMDExMDEgMDAxMTAwMTAgMDEwMDAxMDEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDExMDAwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDExMDAwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDExMDAwMTEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMDExMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMDAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDExMDAwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDExMDEwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMDExMDEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMDExMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDExMDAwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDExMDEwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMDAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDExMDAwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMDAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDExMDEwMTEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDEwMDAxMDAgMDExMDEwMTEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMDAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMDExMDEgMDExMDAxMTEgMDEwMDExMTAgMDEwMDAxMDAgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMDEgMDExMTEwMTAgMDExMDEwMTEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMDExMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMDAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMDEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMDEgMDExMDExMDEgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMDExMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTEwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMDAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDExMDEgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMTAwMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMDEwMTAgMDEwMTAxMDEgMDExMDAxMTEgMDEwMDExMTAgMDExMTEwMTAgMDEwMDEwMDEgMDAxMTExMDE=