It's good for a cleaning (White vinegar) If i lay some tile and grout it the next day they will be a white haze over the tiles from the grout. Mop it with water and it doesn't remove it. Make a 50/50 solution with white vinegar and water wipe over it with a sponge and the haze is gone and it doesn't come back. Good cleaning agent.
"Pickling" (that is the correct term here) certain types of metal, to remove oxide or lime scale. Vinegar is not too strong so carries less risk of harming the metal itself, and I think it is more effective on copper and its alloys than on other metals.
I'm not sure I'd use it as a drain cleaner as suggested by Bozette, as alkalis are better than acids for removing fatty deposits. Don't use both at once as they will merely neutralise each other.
And I use washing or even caustic, soda, rather than baking soda, as a drain cleaner because although all three are alkaline, baking soda is quite weak.
Vinegar's quite a good window-cleaner, too.
Re Baba's suggestion for using vinegar to remove salt from the eyes. I agree with Element99. It won't work and in fact is more likely to be an irritant than the salt. As Element says, use plain water - I use water straight from the tap if I need to wash my eyes out in a hurry. Once the worst of the contaminant has gone, tears will naturally take over to finish the task.