1000 Heroes is an iOS game where you run time trials in a platformer style. The hook is that there is a different one each day, for 1000 days. I've enjoyed playing it while waiting for the bus home after work for the past few months and I finally reached 5 hours play on it. It takes a long time to get to when you only play for 5 minutes a day max.
That said, it's getting a little samey. Every so often the age changes, but not nearly often enough for the game to stay fresh. It's day 145, which is a little over 3 months, and I've played it for a lot of those days and it's felt a little like a chore for a few weeks. The developers have painted themselves into a corner with setting out all the ages on the app for everyone to see, which means it's difficult to swap things up to keep it fresh. I really, really can't see myself playing for the 855 days left.
1000 Heroes is a really neat idea that suffers from the format it picked for itself. I'd like to see more developers use it. A bite-sized dungeon crawler that gives you a new character every day to try the dungeon with? A racing game that gives you a new track every day, similar to Trackmania (free, by the way)? Maybe a mix of Timesplitters and Borderlands - switch up giving you new characters and new weapons? There's a lot that can be done with drip-feeding content to mobile gamers - if I can come up with these ideas, surely some talented developers can come up with better.
1000 Heroes gets 3/5 stars.
(Oh, and someone PLEASE PLEASE make that dungeon crawler. I would sell my firstborn for that shit.)