sandei - a shortcut for {spano djedi}, Spanish day, a reference to full cultural neutrality of this system of weekdays.
tuzdei - location day (a day symbolizing a firm place taken by Lojban, everyone knows how useful Lojban is in our world and where to apply it)
vendei - seller's day (optimal day for selling copies of CLL, the reference grammar book of Lojban)
sozdei - 9th day (probably, traces of an ancient calendar where week had days numbered from 0 to 9)
fradei - reaction day (a day devoted to various reactions of Lojbanists to weekday and other proposals, see also {
besto} )
satydei - sugar day (also known as cake day)