Plickers is a powerfully simple tool that lets teachers collect real-time formative assessment data without the need for student devices.  Plickers is available for free for Android and iPhone (and works on iPads too). Rather than responding online or with an app, they hold up cards, which are their "paper clickers" (a.k.a. Plickers). You can print a set 40 or 63 cards from for free (or buy a nice set on Amazon). Each card is numbered, coded, and marked with A, B, C, & D. Students rotate their assigned cards so that the letter for their response is at the top. The teacher pans the room with her device as the Plickers app scans using the camera. Plickers instantly recognizes each card and logs its chosen letter. Plickers has a companion website where you can associate each of your students with a card number. The website keeps track of every question and response. You can review each student's response history in a Plickers.com’s score sheet. The website is also makes it handy to input your questions and display them on a big screen.

Socrative.com is a free web-based service that’s great for collecting student responses. The teacher creates a quiz with multiple choice and/or short answer questions.