There are just so many:
I have to agree about Jason - the writers gave him such great and witty dialogue and Dennis Patrick milked it for all it was worth. I think I laugh out loud over something Jason says in almost every one of his scenes.
I also have to agree about Prof Stokes' first visit to the Old House. His rambling on about the architecture and a drunken furniture maker as Barnabas stands by anxious to get on with things - too funny. And another great Stokes moment is when Cassandra discovers the very much alive Stokes at the Evans cottage, and Stokes tells her to give Vicki the message that her copy of the 18th century portrait of Angelique is a fake because he's discovered the original. The expressions on both their faces after that remark are priceless.
Also have to agree with Eve's scenes where she pretends to be in love with Adam. One of the best of those has to be when Eve cuddles with Adam while secretly making plans to be with "Peter". Every time I see the expression on Marie Wallace's face, it never fails to make me laugh because she's so into being evil and duping Adam.
And again I have to agree about the reading of Edith's will and what transpires afterward. But I think my absolute favorite scene in that ep is when the newly powerful Judith has Edward dragged out of bed in the middle of the night just so she can inform him that she's moving into Edith's room - another priceless scene!
One of the most unintentionally funny moments in 1897 occurs in a scene that takes place in the cottage between Frid and RD when RD completely screws up the dialogue. Barnabas instructs Dirk to, "Tell them that you saw no one here." To which Davis as Dirk says, "Oh that's fine, what am I gonna tell em?" Barnabas replys, "That you saw no one here!" - but he does it in such an exasperated tone that you can't help but see that Frid is really peeved at Davis.
I love when Barnabas' confronts Lamar at the Trask chapel after Barnabas had escaped from being imprisoned by Trask. Frid's glee and Jerry Lacy's terror are just so evident that you can't help but laugh along with Barnabas' obvious enjoyment in getting the upper hand again.
And the sparring between Gabriel and Samantha. Did two other characters ever hate each other as much as those two? It's just such fun to watch.
But I think my two absolute favorite scenes have to be 1) in 1897 when Quentin writhes in agony while Laura glibly recounts the story of her "death" in Alexandria. Diana Millay is such a hoot in that scene - and 2) (do I even have to say it?
) of course it's when Roger calls Jeb "a cheap, insufferable pig!"