I guess this doesn't exactly fall under "what I have done today" but this is what I have done since I purchased my 2016 Sierra SLT Z71 in late December. Just wish it didn't rain before I took these photos so the truck was actually clean.
Leveling kit
Ceramic tint on all windows including windshield
Black window surround
Paint to match mirror caps, door handles, and door bumpers
De-badged everything but GMC logos
Color matched the GMC logo
Weather-tech floor mats and mud guards
All Terrain Grille, painted to match
de-chromed and powder coated front and rear bumpers to match body color
removed front air dam
Amp Research power running boards
Back-flip VP Tonneau cover
Custom magna flow dual rear exhaust with black tips
New wheels with Toyo AT II Extreme 295/55R20 tires
Philips LED back up, bed, and license plate bulbs