One of the mashups that I explored was Spell with flickr. With this application, you simply enter letters (or words) to create a unique picture that represents each letter. I think this would be a fun and engaging activity for younger students to explore with while learning to spell new words.
Here's my name in pictures:
Also, I created my first trading card using bighugelabs. I think the trading card idea would be a great project for older elementary students to make. For example, if students are researching Famous Texans, they could create a trading card on their Texan after their research is complete and share it with their peers.
Here's my trading card:
