Interesting Basemaps? Post them up!

TimDine

Does anyone have some particularly interesting basemaps that they've stumbled across and gotten to work in the viewer?  I'm always looking for new backgrounds to try.  If you have some post them up!  Unique data or visualizations are fun.  I've got a few I've tried recently to get started. 

<layer label="MapquestWebTiled" type="webtiled" visible="true" 
                  alpha="1.0" 
                  url="http://{subDomain}.mqcdn.com/tiles/1.0.0/vx/map/{level}/{col}/{row}.jpg"
                  subdomains="mtile01"/>     
 
<layer label="Toner (maps.stamen.com)" type="webtiled" visible="false" 
                  alpha="1.0" 
                  url="http://{subDomain}.stamen.com/toner/{level}/{col}/{row}.png"
                  subdomains="tile"/>   
<layer label="Terrain (maps.stamen.com)" type="webtiled" visible="false" 
                  alpha="1.0" 
     url="http://{subDomain}.stamen.com/terrain/{level}/{col}/{row}.png"
                  subdomains="tile"/>   
<layer label="Watercolor (maps.stamen.com)" type="webtiled" visible="false" 
                  alpha="1.0" 
                  url="http://{subDomain}.stamen.com/watercolor/{level}/{col}/{row}.png"
                  subdomains="tile"/>   

TimDine

Open Weather Map

<layer label="Open Weather Map Precipitation" type="webtiled" visible="false" useproxy="true" autorefresh="600" alpha="0.7" disableclientcaching="true"  url="http://undefined.tile.openweathermap.org/map/precipitation/{level}/{col}/{row}.png" subdomains=""/>  
                  
<layer label="Open Weather Map Pressure" type="webtiled" visible="false" useproxy="true" autorefresh="600" alpha="1.0" disableclientcaching="true"  url="http://undefined.tile.openweathermap.org/map/pressure_cntr/{level}/{col}/{row}.png" subdomains=""/>  
                  
<layer label="Open Weather Map Clouds" type="webtiled" visible="false" useproxy="true" autorefresh="600" alpha="0.5" disableclientcaching="true"  url="http://undefined.tile.openweathermap.org/map/clouds/{level}/{col}/{row}.png" subdomains=""/>  

Not really basemaps, but they're global.