Earn 3000 United miles for signing up for United Mileage Plus.
Most of the signup bonuses that United offers require a flight, and usually an expensive one at that. This one doesn’t. I discovered this offer from an affiliate marketing website, and United’s marketing materials say “Miles for Everyday Activities” and “Enroll today. Get 3000 bonus miles.”
Because it’s through an affiliate marketing page, Mileage Plus will actually pay me $3.50 for each person that signs up through the offer. (I don’t know any way to link to the offer without the benefit to myself.)