I've been thinking how to "refresh" line4 games here. I have searched the internet for some unusual variants of line4, and reported to Fencer as soon as I had found something interesting. Now, after holidays, I'm full of new ideas that I want to share with other players:

*** A mix of line4 and connect6. It combines line4's board, gravity and goal, and connect6's number of placed discs.
*** Same as above, but the goal is opposite (like in anti line4). The rule "do not put in the same column your opponent did in last move" is not applied.

I've been thinking about some additional features, because putting 2 discs a turn is much more challenging and tricky.
In order to balance chances there are two things that could be done:
*** A player, instead of putting his two discs, puts one disc of his color and is allowed to destroy any other (his or his opponent's) disc that is on the top of a particular column. Beacuse this feature enables 3-fold repetition, when the same situation occurs for the third time, the game is a draw.
Example: White starts by playing e1. Black plays c1 and destroys white's disc in e1. The c1 disc is the only one on the board now.
*** A player, instead of putting his two discs, puts one disc of his color, and is allowed to put two NEUTRAL discs (both in the same column) in a column of his choice. These neutral discs are just blockers, they don't belong to any player, and they cannot be used to create a line of 4 discs.

Of course those blockers should be limited by adding the tetris feature, and:
*** to 2 uses/player/game;
*** no more frequently than once in 5 moves.