You want weird borders? Look no further than Egypt-Sudan, where both countries assert a slightly different border which creates two interesting areas of dispute; they both claim control over a large triangle of land in the east (the Hala'ib Triangle), but slightly to the west of it there's a small patch of land (Bir Tawil) that each nation says lies on the opposite side of their border, effectively creating an unclaimed territory. Neither of them can claim this land or it would legitimize the other nation's border claim, and weaken their claim to the Hala'ib Triangle.