Twitter is a pretty useful tool for finding out about things happening in real time. It turns out that it is also a powerful tool for finding out about things around you. You can use search operators to search for tweets that have been geotagged with location information.
If you find that certain twitter addicts are blocking up your results because they tweet too much in that location, you can exclude them. To search for tweets within a kilometre of Dublin Airport, but exclude the users twitspammer and anothertwitspammer, use a minus sign before the search term.
geocode:53.427392,-6.243681,1km -twitspammer -anothertwitspammer
Often it can be better to search by location rather than use #hashtags. As #hashtags start to trend, spammers start to target them, making it harder and harder to find useful information.