Need some ideas

I'm trying to write a racing game that would be very entertaining. I don't really know what would be a entertaining challange for the user because the typical "pass through obstacles and collect stuff" isn't very fun, but for fancy AI stuff or fancy graphics and effects: QBasic might be too slow. I want it to be simple and entertaining for the player. Any ideas?

Here is what I have so far:

Left mouse button: Drive
Move mouse: steer
Space bar : Jump ( there's a problem though, if you hold the space bar, you can fly :D )

DEFINT A-W
DEFLNG W-Z

DIM mb, mx, my
DATA &H8BE58955,&H78B0C5E,&HD88933CD,&H890A5E8B
DATA &H85E8B07,&H5E8B0F89,&H5D178906,&H8CA
DATA &H8EA800B8,&H31FF31C0,&H36B0B9C0,&HCBABF3

DIM m(11) AS LONG
FOR i = 0 TO UBOUND(m)
READ m(i)
NEXT
DEF SEG = VARSEG(m(0))

SCREEN 9, , 1, 0

d = 10
x = 250
y = 150
z = 1
z1 = 500

CALL absolute(2, mb, mx, my, VARPTR(m(0)))
z2 = 100
j = 1
DO
t! = TIMER

CALL absolute(3, mb, mx, my, VARPTR(m(0)))
IF mb = 1 THEN
z1 = z1 - 1
x = x - ((mx - 320) \ 4)
END IF
IF z1 < 10 THEN EXIT DO

IF INKEY$ = SPACE$(1) AND j = 1 THEN j = 10

IF j > 1 THEN
j = j - 1
y = y + 7
ELSE
IF y > 180 THEN y = y - 10
END IF

CALL absolute(VARPTR(m(8)))
LINE (((x - 250) * d / z1) + 300, y * d / z1)-(((x + 250) * d / z1) + 300, y * d / z1), 7
LINE (((x - 250) * d / z1) + 300, y * d / z1)-(((x - 250) * d / z) + 300, y * d / z), 7
LINE (((x + 250) * d / z1) + 300, y * d / z1)-(((x + 250) * d / z) + 300, y * d / z), 7

LINE (300, 220)-(340, 220), 12
LINE (300, 220)-(270, 350), 12
LINE (340, 220)-(390, 350), 12

LINE (320, 230)-(320, 250)
LINE (320, 240)-(400 + COS((320 - mx) / 150) * 15, 240 - SIN((320 - mx) / 150) * 15), 15
LINE (320, 240)-(240 - COS((320 - mx) / 150) * 15, 240 + SIN((320 - mx) / 150) * 15), 15

PCOPY 1, 0

1 IF TIMER - t! < .05 THEN 1
WAIT &H3DA, 8, 8
WAIT &H3DA, 8
LOOP UNTIL INP(&H60) = 1
SYSTEM