The rules are simple: If you see a skin/champ/joke/hint during the loading screen, there must be an action you perform.
For example:
Whenever I see [Ruthless 
], I must [play the theme to He-Man and the Masters of the Universe]
weihe1232 voteswhen ever i see a frostblade 
, i must play "Baby got Back"
Addy the Cat2 votesWhenever I see Armor of the Fifth Age 
, I must play "It's Raining Men".
Wildfire GoG2 votesWhenever i see a 
.... oh wait....
uhm.....
Nevermind...
exiledFromBadmen1 votesWhenever I see 
, I must play "Can-Can"
A Seductive Dodo1 votesWhenever I see 
, I must watch Space Jam.
Edasich1 votesWhenever I see 
, I must take a deep breath and calm down, because otherwise, I might try to murder a dog.
TerraRising1 votesWhenever I see 
or 
I must play "Hooked On A Feeling."
CrystalKamu1 votesWhenever I see any sort of 
on the loading screen, I need to hug the tree in all chat once I'm loaded in. ouo
Cu Sidhe1 votesWhenever I see Project Yasuo on the loading screen the only thing I know for real is THERE WILL BE BLOOD!
https://www.youtube.com/watch?v=plgx--ABInA
I honestly play this for the entire match XD
Shadowchaser991 voteswhen i see 
I play this video
http://www.youtube.com/watch?v=Xpe-JoGyPsY Cant kilian the Zilean