I have a habit of sticking random fruit seeds in pots on my window sill and not marking what they are (mostly because i feel they won't grow anyways!). Now looks like this guy has began to grow... and i have no idea what it is! The seed was pretty "husky" and is in the first photo! I feel like it might be some citrus? Thanks for your help!
Most definitely not a citrus. Seed pod looks kind of like a flowering maple - abutilon. Leave is iffy as there are so many variations in shape - are they soft/fuzzy?
I think you have a flowering maple. If you acquired the seed from outside then there is a good chance it survive in your garden, if not then you have a new houseplant :) http://www.thegardenhelper.com/abutilon.html