... I wish I could find more to do with it. The only game we actually own two copies of in this household is Mario Kart, and we play pretty much constantly. We do rounds of Download Play Meteos occasionally, and it's okay, but it's not a sufficiently varied experience for us to want to buy another copy. Most suggestion lists for games to play together start with Mario Kart, mention a couple of games with apologies that they're so-so even in the minds of the suggestor AND require two copies, and then trail off in despair.
A long time ago there were hints of Gauntlet DS, and that could be fun, but it's been constantly delayed, probably due to encroaching suck. Wah.