Restarting speakers without rebooting?

My MacBook Pro internal speaker has crashed, as it does every few months. I'm sure a reboot will fix it, but wondering if there's any way I could restore the speaker without rebooting? (Setting things back up again is time-consuming.)

UPDATE: It didn't actually work after reboot. I noticed the headphone slot is red, like in this picture, so it seems it's trying to serve optical out, since MBP uses the same slot as explained in that thread.

UPDATE 2: Best solution I've seen is here. https://discussions.apple.com/thread/4220803?start=0&tstart= Note that it's fiddly and you might need to reboot before re-trying the headphones.

Sometimes changing the sound output from your system preferences > sound panel will reinitialize the connection to your hardware. If you only have one output device available, try installing soundflower, just to have a second output in your list that you can cycle through.

Also: setting things back up after a reboot is a snap with snow leopard. It can remember which apps you had open and reopen them for you.

Try restarting the daemon process that processes audio by typing in Terminal:

sudo killall coreaudiod

This should reinitialize the audio and perhaps reload drivers.

Try quitting CoreAudio from activity monitor, forcing it to relaunch itself.

This answer is based on a comment on @morphos' answer.

Headphones work, but it doesn't work when I take them out. The prefpane changes to "Digital Out" of type "Optical digital out port" and doesn't let me even change the volume. (the volume controls faded and hitting volume keys shows a crossed out sign)

That means that it thinks you have an optical toslink cable connected. Hold down option and click the volume button in the menu. Now select "Internal Speakers"

Alternatively, you could go to System Preferences > Sound > Output and select Internal Speakers

Are you using headphones with your MBP? This thing happens when you take the phones out? Just plug them back make the sound go up and down gently pressing F11 or F12 (a few keystrokes). Unplug it and keep pressing the F11 or F12 keys until you hear it...