Asking a Professor to sign me to a group
Send another email stating that you have been unable to find anyone and have been refused by a few teams. You will try to "catch" him before class.

Then (choose one) if you don't get a suitable reply:

(a) Show up at his office in the morning before class and present the problem. Ask for a solution. I.e. "How should I proceed?"

(b) Catch the prof in the hall just before class and ask for a solution.

(c) When class is about to begin, raise your hand and ask for a solution.

(d) After class catch the prof and ask for a solution. 

There isn't really much else you can do. Prefer a to b to c to d, I think. But, I assume the prof has seen this before. You might not be the only one with the problem so a group might be formed immediately.