A few suggestions:

- First, consider in investing in a license for Dundas Controls. These folks sold the stripped down version used in reporting services to Microsoft, so they know the technology. Their current control set is very feature rich, with nice rendering capabilities.

- You'll want to do a "bar chart", where you're converting the times down to a fine enough level of detail. With the Dundas controls you'll have more options of text over, auto movements, etc. but I believe you can achieve the desired effect in the stock control.

- With "short time periods", you'll probably want to put the longer labels into a text popup. In general (for ease of design), I'd stick with session Ids (i.e. MAT101) for the fixed labels, and if available put the longer definition in the text popup (i.e. Mathematics 101, Room 12) or a legend.

- You didn't say what your export or print expectations. For export, I'd restrict it to PDF (why worry about the Excel in this case). Printing almost demands the legend.

Good luck.