On the playground there is a Llama in a sandbox next to a radio. When the radio is pressed it plays an instrumental version of "Havana." To teleport to the Llama type "setpos_exact -1494 -3082 -185" in console.

After digging further I found the ambient generic for the music is called "music_lama" while the Llama is simply a prop_dynamic. This may be a reference to the billboard near spawn (setpos_exact -13129 12544 1825) but there's no way of really knowing.