Oh yes there was that, the good old Fastrack system, it's what Disney use!
Not quite Q-Bot though - that is where you get a little handheld device like this:
You can then select a ride you want to reserve and you wait the same legth as the queue, but can do other things in the park. It then notifies you when it is time for you to ride. If you pay extra then you can get upgraded ones whereby it cuts the queue length by a certain percentage or for the top level ones it will remove the queue time totally! You can only have one ride reserved at a time though.
I've used the system before at Six Flags Great Adventure - it works really well!