You can have a look at the Clinical Trials Network, where data are available in CDISC format. You must agree to their terms and conditions, although the following point might be of concern for teaching purpose:
To retain control over the received data, and not to transfer any
portion of the received data, with or without charge, to any other
entity or individual
(Anyway, I think that you can just send an email to the contact support to check that their data can be used for teaching.)
The NIDKK Data Repository is specifically concerned with studies on kidney and liver disease, and diabete; however, you have to submit an application.
Otherwise, perhaps the ADNI project, which aims at characterizing change in cognitive functions and brain structures with age, with a particular emphasis on Alzheimer's disease and neuroimaging, might be interesting. This is not a clinical trial, but available data include: demographics, clinical and cognitive data, neuroimaging (MRI/PET) data. Details about protocols and data can be found under ADNI Scientist's Home, and data are available on ADCS website.
There doesn't seem to be anything related to RCTs on http://www.infochimps.com/. However, I remember having seen some clinical data used with the Weka software, as e.g. on this page: Data mining to predict patient outcome in a clinical trial of a lung cancer treatment.