It's been about 50 years since a bunch of bands made their way across the pond to America, sending the nation's teenagers into a tizzy - as well as their parents into a harrumph. Now, many of the figures from the era of the British Invasion - including Peter Asher, a renowned producer and the former half of the duo Peter & Gordon - are hitting the American road yet again for a 50th anniversary tour, coming to the Pabst Theater on Friday, March 6.