I'd like to offer you one simple idea to have fun with the beloved person.
If you spend a lot of time together and don't know what interesting you can do together, you can try this idea.

Take two pieces of paper, marker or just a pen, and a silk scarf. Now both of you should make the portraits of each other, but with the eyes blindfolded! You shouldn't be a good painter to make it as this idea is just for fun, and I'm sure you'll laugh a lot after you see the pictures!

It's also possible to draw a caricature on each other. In this case, you should see what you paint, that's why you don't have to blindfold the eyes.
In both cases good mood is guaranteed!