The problem with that is most tickets won't get to you that day unless you pick them up, and most sites stop selling them a ways before the event just to avoid issues where you don't receive them. Maybe "Where can I go this weekend for $X"?

Excuse my ignorance per this industry, but what about a Will Call or prepaid option for the scenario zackattack mentioned?

No problem and the they are getting better with this. Stubhub and some of the other providers offer etickets (they email you the tickets). Stubhub also has something called Last Minute Services where you can pick up the tickets up until game time. Unfortunately, they don't do this for most events.