I think a caricaturist is a great idea as it can also be a great gift for your guests! I always wanted to get a caricature of myself but just never happened to do it, so if it was there at a wedding I would definitely use that opportunity to get one.
I guess it could also be a good idea if you wanted to do different "entertainment" stations, like one for a photobooth, one for caricatures, etc. Is that the idea you had in mind?
I also give more idea of games in these discussions: