Alphabet & Numbers Board
There’re plenty of stuff out there (posters & electronic toys etc) that do very basic literacy skills but you can easily get one hanging on the side of your kiddo’s cubby hole in 30 mins.
Egg crates are great material to work with. Not only are they readily available but also ‘pops up’, surely that beats looking a a flat poster of alphabets and numbers. Should you have more time, you may replace the flaps with velcro tabs and kiddo may then match the alphabets with corresponding pictures in a simple ask-&-identify game.