**We all know this is a time for festive cheer. But in Ireland the presents can wait and the turkey can be left to go cold, because there is only one thing that matters over the next few days, and that is derby day.**\n\nThis year the two clashes seem as crucial as ever, with Munster and Leinster facing off in Limerick on Saturday, with both sides unbeaten heading into the weekend, while Ulster and Connacht do battle a day later. \n\nWhenever any of these four go head-to-head it is always a spine-tingling affair, with local pride at stake, and so often these matches go some way to deciding who will be leading the conferences at the end of the season. \n\nEven after the final places have been decided, the four have regularly clashed in the final stages of the season, which makes the times these sides come together more rip-roaring than most. \n\nMunster fans won’t need reminding of the fact that they have missed out to Leinster in the semi-finals in each of the last three seasons, as Leo Cullen’s side continue to be a thorn in their side. \n\nWhether it be in Belfast, Limerick, Galway or Dublin, everybody stops what they are doing when there is bragging rights at stake, with the palpable atmosphere emanating right through to the field, and the drama never-ending. \n\nClashes between Connacht and Ulster have been just as fierce over the years, with emotions always riding high whenever one of these sides crosses the border to face the other, and this year will be no exception. \n\nThe spoils have been shared in recent history and with both sides starting this season promisingly, the clash at the Sportsground on Sunday is destined to be another classic to add to the list. \n\n# The battle of the unbeaten at Thomond Park\n\nThis is the one we’ve all been waiting for, the meeting of two of the unbeaten sides in the Guinness PRO14, in the latest instalment in one of world rugby’s longest and bitterest rivalries. \n\nThese two have been butting heads for generations, with Leinster just about edging the head-to-head records between the two, with 54 victories from the 102 meetings since the end of the Second World War. \n\nAnd despite their recent dominance in the fixture, having emerged victorious in 11 of the last 13 duels over their rivals, Leinster will have to be on top of their game if they are to return from Limerick with the points on Saturday. \n\nIt will be almost two years to the day since Johann van Graan’s side last tasted success over the all-conquering Lions, when Joey Carbery’s superb performance with the boot backed up tries from Chris Cloete and Keith Earls in a 26-17 victory over their 14-man opponents after James Lowe’s red card. \n\nThe records keep tumbling for this Leinster side of late, with victory after victory coming their way in the Guinness PRO14, while they collect bonus-points week after week, as well as performing in European competitions. \n\nWins over Montpellier and Northampton Saints gave them the perfect start in their quest to conquer the continent in the past fortnight, and will have set them up perfectly for the mouth-watering tie in store this weekend.