What's a good CS undergraduate thesis topic that can be done solo?

What's a good CS undergraduate thesis topic that can be done solo?

I'm a computer science undergraduate who stopped schooling on my senior
year because I had to help my family with finances by getting a full-time
online job.
Now I have completed everything in my course and passed all my subjects
EXCEPT my thesis. So next semester, I'll be going back to school so I can
finally finish off my bachelor's degree. But I'd like to get ready for it,
and gather as many topics as I can find so I can choose from all of them.
Oh, since my old classmates are gone now, I think it would be best if I
work on my thesis alone since I do not know anyone else in the current
batch.
My specialty is web development with PHP/SQL/Javascript/AJAX, but I'm also
good with C/C++ and Java. I do have some experience with mobile
development (Corona SDK), but not as much to say that I'm an expert in it.
I don't have much knowledge when it comes to networking and hardware sooo
probably none of that.XD
I'd like to ask for your ideas. I've searched around online for a long
time already, but I really don't know what I'm looking for. :( Please
help.
tl;dr: Would like to ask for ideas for a good thesis topic that can be
done solo.
Thank you!
kazuo