The Cheat's Keyboard
From Homestar Runner Wiki
The Cheat's keyboard is a Casio SK-1 (alternate link) portable sampling keyboard. The Cheat has played the Strong Badia National Anthem, a background beat for Strong Bad's chart-topping hit "Song About Sibbie," and the acoustics for "Everybody Knows It" on it.
The Cheat's keyboard appears to have an extra key between E and F and two extra keys between B and C. It also seems to be able to generate sounds from the Casio MT-100.