With VoiceThread, you can record engaging presentations and interactive lectures that include PowerPoint slides, images, and video along with voice-over narration and on-screen annotation.  It is also a collaboration tool that allows students to add audio/video comments to your VoiceThreads.  For a flipped classroom experience, you can pre-record a lecture and assign it in advance, leaving more time for classroom activities.  VoiceThread is a cloud application with no software to install.  It's available to all faculty and students.