Upload your pics to MarvelStudiosHeroActs.com and stand a chance (*for a trip for 2) to walk the Red Carpet at the Hollywood premiere of Marvel's Guardians of the Galaxy Vol 2 ! Contest ends 2/28/17, limited 100 pics per account! (Full entry details here).
Running parallel to this was a campaign from Marvel, by which they will donate $15 to Save The Children for every post. The deadline ends Dec 10th, and the monies raised so far is “$446,205” (as of this post) out of $1 Mil max.