The Tavern is one of the few places on Mill that's just as good during the day as it is at night. During the day, they have some good grub- I've enjoyed eating lunch there many times (grilled chicken sandwich... nom nom). The service is great and the managers have even come over to the table to say hi.
At night (or before an ASU football game), The Tavern is a great place to party. They have patios so you can be outside and the tunes are playing which usually gets a nice group going on the dance floor.