How much fun can one squeeze into a holiday weekend?Johnny’s Hideaway packs a dance floor full -- and then some -- in a pre-Memorial Day bash on Sunday, May 29 beginning at 8:30 p.m. Band X, Atlanta’s favorite high-energy party band, provides adrenaline-pumping music, and cover is only $5. Hospitality workers enjoy Sunday night industry specials. Open into the wee hours of Memorial Day morning. Can we rank a salute for that?