Type out a message using the shape of buildings around the world
http://www.geogreeting.com/main.html
Google Map and Gov Data mashup
http://www.schoolmap.org.uk
uLearn has been created specifically for schools Teaching with maps (whether on the whiteboard or using a set of personal computers) makes learning much more visual, exciting and personally relevant.
http://ulearn.infomapper.com
create short map links - the easiest way to share locations in posts, tweets and texts
http://xm.my
Map mashup to display messages at a set location
http://www.mapmsg.com/send/smokesignal