Double roundabouts are reasonably common, but mosly they're small "mini" roundabouts which aren't much more than painted circles on the ground. I like roundabouts as they keep the traffic flowing well (most of the time).
In Hemel Hempsted theres what's known as a "magic roundabout"... try this for size..
It's basically a series of mini roundabouts round what looks like a big main roundabout - very confusing if you first get to it... but all you do is look at the main exit you want to take and then treat the mini roundabouts as individuals until you get there... nightmarish at first but not too bad when you're used to it!! You basically ignore that the big inner roundabout exists... so you can turn right at the first mini roundabout then turn right again to get to the far right exit on the main roundabout......
In the UK we're totally used to the way roundabouts work so it's not such a big deal but I can imagine what it'd be like for some poor foreigner used to driving on the other side of the road and unused to roundabouts to come across something like that!!