The ability to program Android devices in C# using many of the
libraries that you are already familiar with is rather cool.
You may/not have heard about MonoDroid, which is an
implementation of the Mono Framework, for Android. It has
been in a closed beta. About 2 weeks ago, it became available
in an open beta. While there are a number of things that it
doesn't do at this point in time, you can tell that the Mono
team is working towards getting many pieces working. If you
are interested, check out the
MonoDroid web site.