Isn’t Courtney a LOVE! Here’s a humdinger item about her in a posh Vancouver nightclub, leaping onstage to boogie with pal Evan Dando — and ripping her fingernails off with her TEETH, dude! Courtney freaked when long, false nails she’s wearing for her role in the flick “24 Hours” prevented her from playing guitar. One by one, she bit off the nails — ruining a $1000 manicure! And get THIS: When managers told her and Dando their performance was running too long, Courtney got cranky, tore off her blouse — and rocked on TOPLESS as the crowd went wild!