We try to get our son to do as many different activities as possible (within reason). He goes to art class, he goes to music class, he goes to dance class, he goes to the museum, he goes to the park, he goes on playdates, etc. The point is we get him out of the house and doing things so he interacts with other children and learns new things every day.
His current favorite activity seems to be art class. Although he does not particularly care for the part where he gets paint on his hands. He has learned to solve that issue by wiping his hands on his clothes or on his mommy. Then he goes back to painting and then realizes he his dirty again and wipes it on himself. It is a cycle. And the reason he does not wear his Sunday's best to art class. Fortunately the paint comes off of him and his clothes fairly well in the bath or in the washing machine. (No, he has not been put in the washing machine).
When it is all said and done he comes out of class with his "art work" in hand and whatever paint colors that were used in class splattered on his arms, his face, his hair and his clothes. I have to admit I do not always understand how it gets in his hair. Be that as it may, he is grinning from ear to ear. And his masterpiece ends up being displayed proudly on the fridge until the next one arrives to take its place.