Unorthodox character builds are actually my preferred method of play. Been around since beta so I need to keep things interesting.
AS/Hybrid Janna, I play this regularly and I'm known for doing it well. I knock over towers.
AP Cho'gath is beastly, properly timing a rupture + DFG + silence + ult knocks out anyone.
AP Kog'maw is a great nuker as well.
Spellvamp Vlad is my preferred build.
Movespeed Eve! PD/LIchbane/Boots of Mobility, dive in, dive out.
Triple Snowball Kassadin, I've gotten this to 20 stacks once and it was hilarious.
FiddlesTank, works surprisingly well.Rylai's/Spirit Visage/BV/Sunfire/Thornmail/Merc Treads/drain drain drain!
TanKennen, great initiator and has an ability which increases his armor and MR, too
Hybrid/AS/CD reduction Sona. Spam abilities, power chord all day, every day Nashor & Younsoo for CD then go from there
MageWick, with AP and CD his Q hits like a truck.