As for inhaling helium from balloons, the following Balloon Agencies warning comes unaltered:

"Comedy television and radio programmes often use helium as a device to get laughs. This portrays helium inhalation as a fun, safe practice when, in effect, it is deadly. Public figures are influential in the minds of the public and they need to realise that they could either die from helium use or be indirectly responsible for the death of another."

Sources: Balloon Agencies