Lob ball is similar to slo-pitch, but instead of the ball crossing the plate for a strike it must hit a 2' x 3' piece of wood/material. Takes a bit of getting used to, especially if the ball is raining down on you from 20-30 feet. Like a regular game, but with bigger spikes in ugliness.
Ok. Lob ball is what we'd call Unlimited Arc. I've also been in tourneys where they use a mat which is the same function as the wood. We voted the mat into one of our leagues in the offseason, and it was great. So they overturned it mid year.
The mat really makes bad strike calls impossible, and makes hit so much easier to hit, IMO.