Do something fresh. I recommend you try one of these -
1. web server in C# that uses the cross-compile benefit of VS2005 - meaning you should be able to load and execute ASP and ASP.NET code using your server
2. mail server - consisting of 3 fragments - SMTP, POP3 and IMAP4 servers
3. FTP server - of course you know what this is
4. A clustered processing application - basically make a program that uses multi threading and each thread solves one part of the problem that is provided
5. Make an emulator - you have lots of choice on this point itself - 8085, 8086, 386 or PIII class. PIV core sources are not yet released, so thats out of reach.
Program 4 and 5 should be real cool fun - try it out you may be able to really learn something that fills a good page in your resume (you'll need to write an explaination - its not going to be a single line thing
)
Have fun,
Chaitanya