I installed some sweet hello kitty dolls on my front and rear dash the other night...

I've taken off my car's front + rear bumpers, headlight, foglights, and tail lights and put them back on (mainly to replace burnt bulbs here and there).

Lubed my sway bar bushings, which means I had to take them off and put them back on.

Replaced my suspension with the help of a friend.

Installed wheel spacers.

Installed bolt-on parts like a strut bar and an intake. Lolz this should count too.

I am not afraid of work on my car as long as there is a DIY. Thank god there is an entire forum for the Lexus IS. If its a bigger job, I usually ask my friend who works at a shop to give me a hand or teach me to do it.

Working on your own car is a large portion of the fun in modding. Once an install is done, it feels very rewarding and satisfying too.

I've done a bunch of simple bolt-on for my cars. (strut bars, exhaust, intake)
Maintenance on my cars. (oil change, dif, tranny, brake, clutch, coolent flush, brake rotors+pads)
Changed the shock+springs few times on my integra and coil-over install on my silvia.
Bunch of suspension bushings and steering rack bushing. Extended lugs
Giving mechanic friend a hand with my 5 speed swap on my integra.

Then there's a bunch of random stuff like taking apart bunch of different panels, taking my bumpers off and putting them back on a bunch of times to either paint them or to do some work behind them.
Or just adjusting the idle of my car and installing some Recaros :D
All of this was learnt from the internet and/or asking someone about suggestions or tips.