as what i can already see in your profile you're already a Jr.member which is also the lowest rank required to be able to join a campaign tho i have read some topic in here that the admins are doing some changes to prevent "trash post" or those people who just keep posting with nonsense stuff just to increase their activity counts/rank.
regarding to your question, you can look for some forums in here where you could find a list of signature campaigns but i just forgot where it's exactly located. just try to roam around the Altcoin (bounty) section "i think" then you could try to look in there or even to try to ask people who are posting topics on that section.