Best odds you've failed to overcome

4 entries I believe.

90 (http://www.steamgifts.com/giveaway/YvdnH/sanctum-penetrator)

Mine is 1 in 35. One of the Railworks 3 giveaways. 2.86% chance to win.

11

Worst one eh? I lost one that had 3 entries!

I may have lost a giveaway with 2 entries. Either way, I've lost several giveaways with less than 10 entries.
EDIT: Confirmed that 2. Puzzle giveaway for Cogs.

1 out of 6

24 for me.

1 out of 4

1 out of 14

2 entries private (multiple times), 49 public from the recent ones I looked at.

EDIT: Found slightly better odds than 50/50, a group giveaway with 10 copies and 19 entries....

1 out of 9

Lost 4 copy giveaway that had 5 entries, and a 15 copy one that had 17 entries..

4 copies of a game and 5 entries and I lost.

http://www.steamgifts.com/giveaway/Zwjii/borderlands-the-zombie-island-of-dr-ned
18 entries, 3 copies.
Had 1 in 6 chance to win (16.67% off the top of my head?) but no dice T_T

1 out of 4

Tons for less than 10.

Last night a private giveaway. 15 copies of Defence Grid! 32 entries. about 47% chance for me to win. WAS SO EXITED but noooooo no green bar for me.

1 out of 2.

Dawn of War - Platinum Edition with 6 entries

ARES: Extinction Agenda (10 Copies), 16 entries.

1 of 25

2 copies of... uh, something which had 19 entries.
Also Portal which had 10 entries.

1/3

Yesterday I lost a 1/2 giveaway :P