Here's one that sounds like a blast from a futuristic laser:

Code:
blast:                                    '
soundcalc = $FD    : sndcnt = 0            'make blast sound
@ movlw     0x8F                        'set the start frequency
@ movwf     _sbuff                        '
xxxxx:
@ incf        _sndcnt    ,F                    '
IF sndcnt = $25 THEN return                '
@ movf         _soundcalc     ,W                'calc the next sound
@ addwf     _sbuff     ,F                    '
@ call         _audo                        'make sound
@ decf         _sbuff    ,F                    '
@ incfsz     _sbuff    ,F                    '
@ goto         _xxxxx                        'check for exit blast routine
@ return                                'exit when sound is finished
audo:
SOUND portc.7,[sbuff,sbyte]                'output sound
@ return

'