Kittypalooza, an annual benefit concert for the sick, injured, and abused cats cared for by the Tree House Humane Society, takes place Friday night at the Double Door (1572 N. Milwaukee). This year’s lineup will be Brice Woodall, the Goldstars, Old Dog Music, the Great Sea Serpents, and LaSalle. The concert’s free, but a $5 donation gets you a CD from one of the night’s acts. There will also be a raffle ($3 each or two for $5) with prizes like gift cards to Sam’s Wine and Spirits, messenger bags by Gravis, and Tree House merch for humans and cats. Kitty-themed drink specials (Pink Pussy Cat, anyone?) and complimentary snacks will be available all night. Doors open at 8:30 PM. Call 773-784-5488 for more.