I love this thread. Here's my first idea. I put in those fancy holographic game mats in bowling venues, arcades and even the karaoke places because they fill up the fun need so quickly. I work my career sims pretty hard so they often need a quick fun fix after work.
Also if you have a wealthy family and want to move out and play the grown up kids or roomies with simoleons in their pockets, put several virtuoso violins in their inventories. It gives them a nice nest egg.