This game is really fun and interesting.
It's more fun to watch TV than chatting while eating.
Jumping out of an airplane is so much fun!
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.
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!