Powerpoint used to be the desktop program for demonstrating mastery. There are many more web based services that can be used instead of powerpoint. Below are a few powerpoint alternatives.
Prezi
Prezi is a good alternative to powerpoint. The latest changes make creating a Prezi easier. You can allow your students to create an account if they have school email. If your students don't have school issued email accounts another option is to setup one gmail account. Then you can go to http://notsharingmy.info/ and create as many email accounts as you need. Be mindful that you will need access to the email account to confirm that you signed up for Prezi. Of yeah and make sure you scroll down and click on student and teacher licenses.
Animoto
Animoto offers teachers free pro accounts that you can use with your students. This will allow students to create videos to present their findings. The ability to add audio, music, and pictures can help engage your students.
Weebly
Weebly is a great resource for kids to use to create a quick website. I have successfully used this option to allow kids to create a website to publish their content. As the teacher you can create an account for each student or each group. Student accounts can be private or public.
The great thing about these three options is that all a student needs is a computer with internet access to use these three services. Most students will figure out how they work rather quickly. If you need assistance in figuring out how they work you can check out the help section on each site.
Share your powerpoint alternatives in the comments below.