QR coder
Free iPad app: https://itunes.apple.com/us/app/qr-code-reader-by-scan/id698925807?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/qr-code-reader-by-scan/id698925807?mt=8&uo=4&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=me.scan.android.client
Website: http://www.spiderscribe.net/
Paid iPhone app: https://itunes.apple.com/us/app/skyview-explore-the-universe/id404990064?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/skyview-explore-the-universe/id404990064?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/skyview-free-explore-universe/id413936865?mt=8&uo=4&at=10l6SU
Free iPad app: https://itunes.apple.com/us/app/skyview-free-explore-universe/id413936865?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/us/app/visualize-free/id456857776?mt=8&uo=4&at=10l6SU
Paid iPad app: http://itunes.apple.com/us/app/visualize/id444076754?mt=8&uo=4&at=10l6SU
Website: http://www.instagrok.com/
Free iPad app: https://itunes.apple.com/us/app/instagrok/id777873941?mt=8&uo=4&at=10l6SU
Google Apps for Education app: https://www.google.com/enterprise/marketplace/viewListing?productListingId=17789+13349884249762973052
Google Chrome app: https://chrome.google.com/webstore/detail/instagrok/flonaffkffjppejcafgpdgilebfikemd
Edmodo app: http://www.edmodo.com/publisher?uid=7493337