There are lots of good bounty program with good signature campaign in this forum. Try to search a litte more a bout the project with creadible team behind it. But to help you out I would suggest to visit this link
http://bounty.slavyansk.biz/ to guide you through which one you would like to join in. Bounties are sorted to date, and you can see every detail in every bounty program campaigns. It's up to you to decide, and there are alson ratings on each bounty campaign. Hope it helps