Ok you have a problem with thinking up of lyrics, your brain just isn't working at the mo. There are two solutions to this; say whatever comes to your head and write it down, or, write down what other people are saying.
Right, lets start with solution one: Say whatever comes to your head and write it down.
This does actually work, believe it or not. Most of the lyrics that I have come up with are from the top of my head. I once wrote a song that was based on not being able to come up with lyrics. Alright, I admit, it was a crap set of lyrics, but at least I had managed to write a whole song.
The best thing to do, is to pick a subject, any subject, and write down your views on it. for example:
Your always quequeing up,
The machine is always out of service,
Talking about service, it's crap
It's a bit of a rubbish subject, but you should get the idea. Ofcourse you may feel strongly about world peace (which I have nothing against) and you could write your views on that.
The next best thing is to write down other peaples conversations. When you're talking to your mates you could write down what your saying. This way you could get pages and pages of lyrics real quick. You could always listen to your parents arguing about money and, well, just their general arguments really. You never know, it could be an interesting (heated yet interesting) conversation. If it's not interesting then still write it down, remember, real life is what makes good lyrics.
You could also make a mental note of the things your parents say to you when they find out that you've eeves dropped on them (it could come in handy!)
Thats all I can really say on the subject of lyrics. Hope it helps!