Functional upgrades/mods

I have had my MBP since the July of 2010 and I have been getting antsy to do something to it. I started out simple with just replacing the OEM HDD with a 128GB Samsung 830 series SSD in June and replacing my 4GB of OEM RAM with 8GB of PNY Optima in November. I have been Googling my @$$ off trying to find other things to upgrade/modify my MacBook, but all I seem to ever uncover is threads about upgrading the harddrive and RAM... I have already done those and I want to move on to bigger and better things. I recently found OptiBay and am going to be installing that as soon as I get the funds, I found one thread on changing the backlight color of the keyboard and one YouTube video of a guy who added a second display underneath the Apple logo on the rear of the screen and am considering doing those two as soon as I get the b@11$ to take that much of my machine apart and hope I don't break anything. Does anyone know of any other cool upgrades/modifications that I can make to my MacBook?