the point is to make it NOT boring. Prepare a great story about Shabbos/Rosh HaShana for the seuda, and make the simanim interesting,
VERY IMPORTANT – SING SONGS THAT THE KIDS KNOW!! you can sing other songs later, but have them start a song that they learned in school. If they DO want to sit on the couch and read let them but if you ask them questions about school, or shabbos or yom tov, and get them involved then you know youre on the right track. sing fun songs. tell them a funny/cony joke or story with funny faces that they will laugh, and have them enjoy Shabbos/Yom Tov on THEIR level, not YOUR level.
warning: don’t slip booze in their cups. it’s tempting sometimes, but, hey, it’s Rosh Hashanah time…