I create a simple search page with the aid of some helper classes for Lucene integration in Spring and an Ajax implementation.
Ajax enables HTML to be changed with server data without the need to refresh the html or complex scripting.
The result is pretty neat: while typing, the search results are already displayed so it is easier to find something. For standard HTML sites this is probably overkill, but for the upcoming Media Center sites where a user has only a remote control available, this is quite useful.
The DWR library is surprisingly easy to use and very complete, thanks to the guys from Getahead.