Fit a hard drive to your PS2
It became obvious when the new slim PS2 came out that Sony had pretty much given up on the hard drive add-on for the system. That doesn't mean you have to give up on them though. Most games can be made to run from the hard drive of a PS2, making life a lot easier. Not to mention saving wear and tear on the DVD drive.
Don't want to shell out your hard earned cash for the official add-on? No problem. Here's detailed instructions on how to go about it, and what you will need to do it. It's pricey, but you may have some of the parts already laying around.
One word of warning: Very bad word in giant typeface at the top of the page. A word some would consider not safe for work. Didn't seem worth dismissing the page just for that, especially given how useful the information is. Consider yourself warned.
Now if I can just get my hands on a network adaptor...