I did something similar at work: live cooking up spreadsheet on projector, fingers dancing across the keyboard like skater on ice, sub menus popping up like fireworks, ignoring the mouse like it never existed. a trick of the trade that saw me through in the past 10 years...
of course it is not just for show, it really helps with my efficiency while using excel. Some of the shortcut keys that worth remembering (for pc) are:
Ctrl-PageUp/Down to get to the next worksheet
Ctrl-Tab to switch between different workbook (better than alt-tab as it stays within excel)
Ctrl-1 property of the cell, good for setting format
Ctrl-F2 print preview
Ctrl + or - adding or removing column or rows
Ctrl [ or ] brings you back to the source of reference
Ctrl ~ formula edit mode, shows all the formula as is, instead of results
