Fun
い adjective
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of pleasure? Well, you could say it's "pleasurable," but I'm afraid that's not what we're going for here. In this case, this word is a little more innocent. It just means fun.
たのしい
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
How much fun did you have? You just had a ton o' (たの) fun!
このゲームは、とても楽しくて、おも白いです。
This game is really fun and interesting.
テレビを見ながら食べる方が、しゃべりながら食べるより楽しいよ。
It's more fun to eat while watching TV than it is to eat while chatting.
飛行機から飛び降りるって、物凄く楽しいよ！
Jumping out of an airplane is so much fun!