I'm here.
A little late though.
Exactly what Caitlin said, like Dunkin's but MUCH MUCH BETTER.
I personally am only there for the donuts and Timbits =D
They're really only found around the eastern border between the States and Canada. Places like Maine, New York, Ohio and probably some others (possibly NH?).
There is also one in Kanadhar for the Canadian soldiers in need of a coffee fix.
My city has the most Tim Horton's per capita =)