The Hotdog Man has been a staple downtown forever (here). Though, honestly, I didn't know about it until more recently. He goes out onto High Street at midnight, and this guy can make a hotdog in about a half-second. $2 with any toppings you want, and you're good to go. There's another hotdog vendor, Byrdman, who does the same, but hasn't been around quite as long.
And then there's the more recent Morgan- town Tacos, who sits outside of Joe Mama's starting at 11 p.m. Check their Twitter because I won a free taco recently!
@candace07 you are the first winner today, stop by tonight to claim your prize
— Morgantown Tacos (@morgantowntacos) December 6, 2012
Bottom-line is that it's made for the drunk college crowd. But, hey, it's probably something you should try before you leave town (holla December grads!)