Puns are never good if you explain them, but . . .
This is Energizer Bunny (you may know him as "Duracell bunny").
Battery is "an assault in which the assailant makes physical contact ".

Puns are always extreme humour to me. Have no idea why the author seems to be a bit annoyed by them.

thanks shilgia, actually i meant the title of the article "pun for the ages"! what is that about?
i think puns can be very funny, but you always look smarter if you scorn them.

Excellent article Shilgia! and after reading it, found this one which might be of interest to the SiTers:
http://topics.blogs.nytimes.com/2009/03/31/words-to-watch-2/

i meant the title of the article "pun for the ages"! what is that about?
I'd guess it's a semi-pun on "one for the ages", a phrase which itself seems to be used almost exclusively by U.S. journalists, especially sports journalists.