Ah the days of being a CS under-grad...
I would suggest the same as everyone else here, make a program with real world applications, do the documentation, manual etc. etc.
I started with BASIC, then moved the COBOL for AS400 servers (used in banks at that time), then VB and finally C++ and Assembly Language...that was back in 2000~2002-ish when I discovered Flash AS and web scripting. HTML, CSS, JS etc. etc. etc.
My thesis for graduation was basically a Choose-your-own-adventure type of game kinda like ero-games from Japan but this was for introverts and juveniles with low social skills. It was used in around 10 public high-schools in my country but the data that came back was 50/50. You can't really try to gauge a persons response to your actions as being brought up in different environments affected the data. It was too much for me and my partner but none-the-less I didn't graduate because I moved to Canada...end of story.