Lance Armstrong-backed photo sharing service Mobli is giving people a chance to win $100,000 by giving up Instagram. The company has just kicked off a campaign called #mylastinstagram, complete with a new site at MyLastInstagram.com.

Users are encouraged to download Mobli (of course), upload a “creative/funny/original” photo, use Mobli’s #mylastinstagram filter, post that photo to Instagram, and tag it with the same hashtag.

“Say goodbye to Instagram, their boring filters, and cropped photos (for at least 3 months, you won’t miss it… we promise!),” Mobli says.

The official contest rules are here.

According to NBC Bay Area, Mobli is going so far as to fly a plane over Facebook headquarters repeatedly with a 100-foot banner advertising the contest.

I doubt the contest will do much to reduce Instagram’s share of the photo sharing space (if the privacy freak out didn’t), but it’s a clever way to get some app downloads, I suppose.

Last month, Instagram topped 100 million monthly active users.