For some reason, there's been a recent boost in projects looking to serve the public interest using crowdsourcing. Perhaps April showers brings May do-gooding. Here's 5 projects in particular that have caught my eye of late:

Distributing Asteroid Spotting

The European Space Agency is asking amateur astronomers to help it keep track of potentially pesky asteroids that could pose a threat to earth and its inhabitants.

“The wider astronomy community offers a wealth of expertise and enthusiasm, and they have the time and patience to verify new sightings; this helps tremendously,” says Detlef Koschny, head of NEO activity at ESA’s SSA programme office.“In return, we share observing time at ESA’s own Optical Ground Station in Tenerife and provide advice, support and professional validation. We’ll assist them in any way we can.”

Because of their proximity to the earth, asteroids and other debris can often be difficult for astronomers to spot, making it ideal to use a distributed network of spotters.

Keeping Track of Those Who Keep Track of Us

OONI is launching a new project to map internet censorship around the world. The effort has ties to Radio Free Asia and the Tor Project and aims to highlight instances of surveillance, censorship, and networked discrimination worldwide. The motivation is to create something similar to Google's Transparency Report, but with more open tools. So far a few instances of censorship have already been reported, including a "feature" apparently used by T-Mobile for censorship purposes.

Reddit Outdoes Make a Wish 

Don't get me wrong, the Make a Wish Foundation - which tries to grant wishes to really sick kids - is still awesome, but there's something cool about the simple kindness of hundreds of strangers pitching in to cheer up a bed-ridden man with a terminal illness. After a request was posted on Reddit, hundreds of folks from across the globe pitched in to send gifts and well wishes. Bravo.

 A Bridge Not Too Far

The Dutch are taking the notion of "pay your own way" to new heights... or perhaps new lengths. An effort in the city of Rotterdam to crowdsource a new pedestrian bridge comes with an interesting catch -- the final length of the bridge will depend on how much citizens are willing to pitch in for the cost. The more funds raised from the crowd, the longer the bridge. So far Rotterdam residents won't be able to take very long strolls, as the bridge as reached just 14 percent of its total goal so far.

 - Eric Mack is a contributing editor for Crowdsourcing.org. He also currently contributes to CNET. In the past, his work has been featured by NPR, Wired, the New York Times and other outlets. You can contact him at eric.mack@crowdsourcing.org. Find him on Twitter and Google+. Also be sure to follow Crowdsourcing.org on Twitter.