DIY Sand and Rock Box by FSPDT. Gdjk -> made this with toilet rolls (aka tunnels) and moon sand instead of play sand. My son loved playing with it. The moon sand cleans up nicely indoors but play sand will be easier to play with when using the small cars.
If you're teaching your toddler the alphabet, you'll want to check out this huge list of playful alphabet activities for 2 year olds! While learning the alphabet, kids had opportunity to learn new words.