Billy Joel and Knicks owner Jim Dolan were two of the bigwigs playing host at luxe July Fourth bashes yesterday. Joel’s, at his Long Island home, was billed as a “sing-along” with the Piano Man, while we hear Dolan and wife Kristin invited guests to their annual Oyster Bay extravaganza to watch fireworks by top pyrotechnic clan the Gruccis. (The Dolans once had Whitney Houston perform at their Fourth fete, and the sound famously went out.) Restaurateur Donatella Arpaia, meanwhile, was having a foodie-lovers bash in Connecticut, we’re told. The frolicking will extend to the weekend: Kanye West plays Revel tomorrow in Atlantic City, where Angel Management and EMM Group will launch the new HQ Nightclub.