Bartleby: My preferred variation against the classical variation of the French Defence is the Richter attack, which follows: 4) Bg5 Be7 5) BxN BxB 6) e5 Be7 7) Qg4, often followed up with Bd3, O-O-O, and either Nf3/h4/Nce2 or f4/Qh3/g4 depending on the position. The prophylactic a3 also features.
Some nice games featuring this variation:
Tarrasch vs Walbrodt, 1894
Tarrasch's treatment here is archetypical of the attacking possibilites of such a position with opposite castled kings. Nicely conducted by Germany's reknowned teacher.
Showalter vs Lasker, 1893
Another example, this time by the Kentucky Lion, Showalter, defeating Em. Lasker the year before his title match bid. I prefer 15) Bd3 to white's 15) Qg3, however.
J Mason vs Bird, 1895
Mason shows the possibilities against a centralized king by a slow and gradual build up before launching the javellin of f4. Note his excellent use of the d4 post.
Showalter vs Jasnogrodsky, 1894
Here Showalter slyly keeps his options open until he realizes which burrough the enemy king will move to, then shifts his enemy forces in that direction (Q-side). In this closed then semi-closed position his twin knights coordinate very nicely against black's surprisingly inept bishops and dominate all the worthy posts.
Gunsberg vs M Judd, 1889
Gunsberg's go at it, using a slightly modified move order but very similar thematic ideas.
Lastly, merely for humor and maybe an idea for Thursday night chess at the coffeeshop, a Schlechter & Pillsbury miniature production, in two acts:
Schlechter vs H Wolf, 1894
Pillsbury vs Chaseray, 1902