Vocabulary: involve

I think involve is a very difficult word to learn, because it has so many meanings and Japanese translations.
In the Longman Wordwise dictionary, one of the examples is "The celebrations will involve thousands of people across the country". How would you translate this into Japanese?
In my electronic dictionary, the S II, I tried "reibun kensaku", and got more than 100 examples. One of them was "The accident involved several cars and a bus." How would you translate this one? What examples are there in your dictionaries?
Visiting LDOCE Online, one of the examples was "Running your own business usually involves working long hours." What other examples are at LDOCE Online? How about at Cambridge Dictionaries Online or at the Newbury House Dictionary?
If we input "involve" in the Visual Thesaurus we can see many related words. Try clicking on three or four of these to find out how they are related to "involve" and which word to use when.
I think many of you have the Oxford Wordfinder. Can anyone find involve in this dictionary? Please tell me if you can!
Finally, please try to use involve sometimes in your blog posts or even conversation.