You can match the spirit of it pretty closely with Perl.
perl -C -e '$|++;X:print chr(9585.5+rand());goto X'
perl -C -e '$|++;X:print chr(9585.5+rand());goto X'
php -r "TEN: print(chr(47 + 45 * rand(0,1))); goto TEN;"Try a different terminal maybe? Works in xterm, xfce, etc, for me. Also, I have LANG set to en_US.UTF-8
The ".5" is because Perl's chr() will convert it to an int by chopping off the decimal portion. rand() returns a floating point number between 0 and 1. That's very similar to what the BASIC program is doing.
s=╱╲;while :;do printf ${s:RANDOM%2:1};sleep 0.001;done