Ah Karolinka,
You do entertain me, I know exactly what you mean, for some reason karaoke is really popular over here, but in the UK we still cringe at the mention of the word.
I find it amazing (and amusing) that here people will belt out songs (in bulgarian and painful english) without a care.
Personally, I know I can't sing so I always say no, but if you are ever feeling the need for it you might try Toucan in Studenski Grad  - its a small but very friendly bar, and I have always found the thursday night karaoke to be a great laugh.  - Watch out for the mad texan!!