Other panels will unleash more random effects that allow you to steal other players' panels, swap panels, or other lead-affecting events. At the end of the game, bonuses are awarded based on such accomplishments as who won the most mini-games or who collected the most treasure. These bonuses are also instrumental in deciding the game's overall winner.
Later, if you want to check out the mini-games without having to deal with the board-game bits, you can go into the Vs. mode, which allows you to replay any mini-game that you've unlocked in the Board Game mode. Unfortunately, with just over 30 mini-games, it's not going to take you long to open them all up. This also leads to some pretty stale board games when you end up repeating mini-games sooner rather than later. Compare the number of mini-games in Pirates' Carnival to the recent Mario Party titles which have almost three times as many mini-games. On top of that, most of the mini-games aren't all that fun, so you'll have little incentive to revisit them.
Another problem with the mini-games is that during the Board Game mode, there is no way to practice the events before playing them "for keeps" (a feature introduced in the Mario Party series a couple years back). Some of the mini-games have rather confusing goals, and the instructions provided beforehand are somewhat vague. Generally, the first time or two you play through a mini-game, most of the time will be spent trying to figure out what's going on and what you're supposed to be doing.
It's nice to see a party game that breaks free from the aforementioned "roll the dice and advance on a board" style of gameplay, and the Othello-inspired premise results in some pretty decent multiplayer action. If only the mini-games that you have to constantly play were more alluring. Fans of the One Piece series will appreciate the extensive amount of voiceover work that appears in the game, including plenty of situation-specific conversations between characters (although sorry, otaku, it's all the English dub cast), and they'll clearly get the most out of this title. Anyone else might want to just dust off that old Othello set that's gathering dust in the back of their parents' closet.