Where Can I Download FREE Dora the Explorer (or Go, Diego, Go) Games for my little brother?

My brother is OBSESSED with Dora and Diego, while he is only 3 and a half, he has become quite proficient at playing a dora game we have on a CD, i'm wondering where i can download more b/c he keeps saying "I wanna play my dora game" but when we put it in, he says he wants "a different dora game" so, anyone know where i can download free dora and/ or diego games?