It's worth considering the range of sources of listening materials available. The following are the typical sources:
You
Your students
Your colleagues
Local interviewees, such as friends and professionals. You could approach representatives of local services, such as the police or tourist services, and ask if you can make short interviews.
Recordings of local announcements from railway stations or airports
Internet recordings
Websites, such as Woices (http://woices.com) and voicethread (http://voicethread.com/), which combine audio with maps and images
Activity 1 has an extended list of listening sources.
Recording speed
One of the many useful features of Audacity is that it allows us to reproduce recordings at different speeds without the pitch changing. It's well worth including slower recordings if you think your students will benefit from it. Presentations could include two recordings: the first one at a slower speed; the second at a faster, more natural speed. Alternatively...