Definition of the verb "to trundle" is "to move along by or as if by rolling"; or rather, "to roll", sounding similarly to his species as a "troll".
The area for Contaminate is currently, not counting global abilities, the largest AoE in the game.
Trundle, together with Irelia, has the highest potential tenacity stat in the game, capped at 61% (up to 40% from his Contaminate), and 35% from any tenacity item in the game, (i.e. Mercury's Treads after being calculated with diminishing returns).
Since his introduction, Trundle went nearly two years before being subject to balance changes to any of his skills or stats. He was finally given changes in the Shadow Isles patch in late October 2012.
Trundle quotes make several references to internet "trolls", a derogatory term for someone who intentionally annoys or offends another person.
His second joke "Don't hate the player, hate the club that's smashing your face!" could be also a reference to that meme. It could be also a joke from Riot implying that players focus their hate on champions, not on their player, calling for nerfs on the forums.
Trundle's first joke, "How much you wanna bet I can whack you from one fountain to the other?", is most likely a reference to the movie Napoleon Dynamite, in which the character Uncle Rico at one point asks, "How much you wanna make a bet I can throw a football over them mountains", while reminiscing of his past in football.