Simplest way to make this only weakly gameable is to allow bids to be entered that are higher than the current minimum so that you can bid to be the 2nd person

Simplest way to make this only weakly gameable is to allow bids to be entered that are higher than the current minimum so that you can bid to be the 2nd person to do work. It's still gamble because you can have people bid artificially low in order to intentionally delay work or give someone more time to do things, but it's likely a better system than failure penalties.