[dpratt]

I'd add a driver for a non trivial binary protocol - I ended up implementing a JVM driver for Cassandra a few years ago, and it was a blast.

[voltagex_]

Working with data as binary is a good test of a high level language skills. When I was playing around with DNS, I wrote terrible code like https://github.com/voltagex/junkcode/blob/master/CSharp/DNS/.... A better way to do it is https://github.com/kapetan/dns/blob/master/DNS/Protocol/Head... - structs, of course.

I'd add reading and implementing a protocol from RFC - it's a great way to start thinking about design, especially if you read the original RFCs and work forward through the revisions and see what was kept vs deprecated.