Louvain-la-Neuve, the village of the second (current) university of my PhD sleeps during the Sundays. Almost everything shuts down, as students disappear from the village to their hometowns during Friday evenings to reappear only on Sunday nights. Since it was getting a bit boring during the weekends in this small village, we decided to visit the nearest country, Luxembourg. We first have to go to Ottignies and transit there to take a train to Luxembourg, that originates from Brussels - Midi station.
Usually, this costs 51.60 Euro/person to go to Luxembourg by train from the village. However, on weekends, the local public transport has a 50% discount in Belgium. This leads to the final price of 35.40 Euro/person in the weekends. One ticket from Louvain-la-Neuve to Arlon (Belgium) that costs 23 Euro for a return trip, and the next from Arlon to Luxembourg for return trip for 12.40 Euro. The transit remains the same though the tickets are broken as the above to separate the local trip from the international part of the journey.
For 4 euros, you may purchase a daily pass that you can use to travel anywhere in the country by bus or train. Hop on Hop off buses and toy trains were not available during our visit, as they start only from April. Many shops were closed on Sundays. Some were closed as it is still off-season. However, tourists were already there. Luxembourg city was quite boring compared to other cities. Even Vaduz, the capital of Liechtenstein, scored better in my opinion. But Luxembourg is still worth visiting once. If you ask me, any country is worth a visit at least once, anyway.