It’s his party, but there’s cake for everyone. President Barack Obama is celebrating his birthday Tuesday, and merchants are (surprise, surprise) capitalizing on the event with promotional tie-ins.

[IMGCAP(1)]Domino’s is offering free servings of its brand-new “chocolate lava crunch cakes— at Washington locations from 11 a.m. to 9 p.m. Just say “happy birthday— to the prez for your gratis sweets.

And Tenleytown burger joint Z-Burger is hosting an “Obama Birthday Bash— featuring giveaway burgers and cake and unveiling a special “Obama Burger.—

The eatery’s Web site notes that Obama has been invited to attend the fete, but something tells us he’s going to have his hands full when he hosts Senate Democrats for lunch at the White House.

Can’t get enough HOH? Get a midday dose of fun and gossip with HOH’s One-Minute Recess, delivered to your inbox daily. Sign up here — because everyone deserves more recess.