I see that GCL 2.6.7 now runs on the Raspberry Pi. (sudo apt-get install gcl; takes about 2.5 minutes -- mostly xfer time.) Getting 'bare' Maxima (i.e., a TTY maxima) shouldn't be very difficult. If there is already an ARM Maxima, then a Raspberry Pi Maxima shouldn't be hard. (Or should it be called Raspberry %Pi ? ;-)