There are a lots of good flea markets in Lahti. For example Lanttila (Keijutie 29), Cetori (Saimannkatu 54), Femmatori (Rautatienkatu 13), Flea markets of the Salvation army (for example in Ostoskatu), Fida (in middle of citymarket and Prisma of Laune) and Launeen suurkirpputori (Ajokatu 65).
If you have got tired to all the city of Lahti and its happenings, one idea is to go to see real finnish forests. About 30 kilometers from Lahti in Lammi there is a hiking area called Evo. In summertime there is also guidance available, I think.
It is regulally arranged concerts with famous artists in Sibeliustalo in Lahti. As well the Theatre of Lahti is usually good but expensive. (All the entertainments are held in finnis language.)
You can ask Lippupalvelu (for example in Sokosbuilding) or informationcenter about the time and the prices of the exhibitions.
For many years the city of Lahti has arranged waterorgans besides little Vesijärvi. You hear the music and the water is flowing in different colours in middle of the darkness.
You can ask the information desk (if it is open) at what time the organs are working.
There are for example lot restaurantships, cafeterias, handicraftshop and simply benches to sit down. Sometimes there are happenings. The area is at it's best in eveningtime expecially in summer time there are beautifull sunsets to be watched sitting in a cafeteria.
There is a medieval church in Hollola ( called the old chuch of Hollola). It is extremely remarkable idea that it has been there forever. (Expecially for me, because my grandparents has been burried to the nearby graveyard.) I think it is open for public daily.
If you get interested to finnish medieval buildings, there is a medieval castle in Hämeenlinna.
Inside the sport centre there is a mall ski museum where you can see some old ski equipment or uniform and learn about the history of it. There is also video presentation with programs from old competition, you can try Biathlon shooting but really, the main attraction here is the ski jump simulator, I got 101 m in my 2nd try which I think is not bad at all.
Pikkuvesku, or Kariranta, is an ideal place to have a walk or have a picnic. Place were the locals relax expecially on summer.
Check out also the harbour nearby.
At Karirannan kesäteateri (the summer theatre of Kariranta) they are playing this summer the Adventures of Huckleberry Finn.
There are beautiful sites to see and that includes the preserved ancient Roman style of roads found in the capital and the buliding are also great. Why dont you come and have a look? You will not regret it.
This is Finland’s Nordic Ski centre, many Olympic champions are coming from this place where you can practice winter sports as cross country ski or ski jumping or the combined of both of them.