or if that's too much use --binstubs to use "bin/rake balls" or if you are really, utterly crazy, use --binstubs AND set $PATH to contain './bin' and then use "rake balls".
You can also use rvm with gemsets and just not use bundle exec at all. I'm amazed how quickly people forget about the things that bundler tries to fix. If you don't have any conflicts across your gems, you can basically use bundler as "just install my gems".
