Here are some suggestions, sources for Modern Physics activities:
Relativity: RelLab from Physics Academic Software
Particle Physics:ChamberWorks (commercial program) simulates particle tracks;
also see Reichert's Modern Introduction to Mechanics (Prentice Hall) for some
track measuring activities (you can buy a pack of large pictures of tracks)
Quantum Mechanics: Dean Zollman at KSU has developed some hands-on Quantum
Mechanics activities as well as simulations (see workshop announcements for
recent AAPT meetings); I have written a QM simulation program which AAPT is
going to publish (if it doesn't appear by the time you need it, I will see if
I can send you a copy).
Martha Takats
Physics Department
Ursinus College
Collegeville, PA 19426
mtakats@acad.ursinus.edu