The Office of Public Works will be streaming the Winter Solstice live from Newgrange. The broadcast will require Windows Media Player, so those of you on a Mac can use the User Agent Plugin for Firefox and Flip4Mac to watch.
The broadcast is available from 08:30 on Sunday 21st.
Edit: Just as I posted this, an article from The Irish Times appeared in my feed reader with more details about the “rebuild” of Newgrange in the 1960’s.