I'll say there is, but not if they are happening when he isn't ready. I don't know what year your son is or his level of talent, so it may or may not apply. There are several events that my son has said he wanted to play in some day since he was a freshman, and they are all pretty much after you commit. They are selective events, the competition is the best in the nation, cool venues, great "stuff" ( shoes, gloves, shirts, hats, backpacks, etc.), good experience, and ultimately, exposure for the draft. Most of these are not during the middle of the year, they are summer before senior year, but we just attended one this month in senior year. The ones I think are worth it once you've committed (and I'm including showcases outside of PG):
PG National
PG All American
Under Armour All American
Area Code Games
PBR Super 60
To be invited to either of the PG events, he will have to have attended at least one showcase prior. The All American is picked from the National, so it really has to be before that.