At 5 p.m. today at the D.A.R. Constitution Hall in Washington, D.C., the George Mason High School Class of 2007 will be graduated, and the commencement speech promises to be memorable. Michael Hoover, the head of the English Department, classroom English teacher, adviser to the senior class and to the student newspaper, “The Lasso,” will culminate an extraordinary 37 year career at the school by delivering his second GMHS commencement address in the last 12 years. Landing his teaching job at GMHS following his graduation from the University of Virginia in 1970, he delivered his first commencement address on the occasion of his silver (25th) anniversary there in 1995. Hoover, who eschewed many offers of better pay to advance into the administrative ranks of major school systems in the region because of his love of the classroom, said he has no firm plans for what he’ll do after tomorrow.