What could I say to my little sister on the computer when I want to be on?

[kittt83]

She does dumb crap like listen to pop music, play flash games, use Facebook way too much. I play video games, make maps for HL2, make models, et cetera. The only excuse I have is 'I have better things to do on it'. And please don't tell me I should let her use it. She gets her fair share.

[sonriel]

set up a time schedule

[theworrier]

You could try reasoning with her. Tell her in advance the time that you would like to use the computer and agree to alternate, in two hour slots for example and make sure you both stick to it.
goodluck

[sciencegravy]

If she gets her fair share, then you must have your fair share, too.

Just because you're older and the things you're interested in seem more important to you, doesn't mean you should get longer turns that she does.

Have your parents' agreed on time limits? If so, then wait your turn. If not, you might suggest they set up a schedule.

[James]

Put a password on the computer so she can't use it. =)
Otherwise...
Say your parents told you to come do your homework on the computer.
Turn the monitor off constantly until she goes off it.