Discover Card is offering 5% Cash Back on Gas, Movies and Museums purchases during the 1Q/2012 period from January 1, 2012 to March 31, 2012.  5% Cash Back is limited to the first $1,500 in purchases for those categories.  Effectively you can get back a maximum of $75.  Sign up is easy – Just login to your Discover card to join or click here to sign up.