Unusual Innertube valve?

What are your options if your mountain bike uses presta valve tubes, but all you have is a regular bicycle pump (with a tip like the kind used on cars)?
Well, first of all you can by a presta-valve pump from a specialty bicycle shop. This will set you back about $30 - $50 bucks -- maybe more.

Another option is to buy an adapter online. These presta valve adatptors will convert a normal schrader valve pump into a presta valve style pump.

Lastly, you can just switch the tube out. Be careful though, because the presta valve has a smaller diameter, and the tip of the schrader valve won't fit through the hole in your wheel rim. In that case you need to drill it out, which can significantly weaken your rim.