My DS's had a PS2 for christmas,they also have game boys.The time they spend on them, seems far more limited than some of their friends and sometimes I feel really mean.
On week days they are not allowed on them before school and after school only, once they have done homework,reading,etc and eaten their dinner.
They go to bed at 7:30pm, so this proberbly only allows them 1 hour at the most, less if they have a bath.
On weekends they are proberbly limited to 2 hours, spaced over the day.Luckily, we are usually in and out alot so they don't get much chance to play.
If they make a fuss about going anywhere or doing anything, because they would rather stay in and play their games,then they get a BAN.
They clearly love playing their new PS2, but sometimes I wish we hadn't bought it.It's just very hard being strict about it when some of their friends are allowed to play all day.