We had a b-day get together at Andretti's in Roswell for my son when he was 8. The party package is pricy so we did our own thing with fewer boys. We did not however do the go carts (again too pricey for our b-day budget). The kids did the arcades and rock climbing wall. We did it on a Sat. night (not very busy at all) for 5 boys. We did pizza before we got there and had a sleepover afterwards. The boys really seemed to enjoy it.
Another option (w/ no go carts though) is Stars and Stripes in Cumming. We had a 9 yr old party there last yr. They have non-birthday package deals. Last year it was $20 for Tuesday evening only but included 100 tokens in the arcade, unlimited laser tag and a small personal pizza. They also have bowling.